Accident to the Robinson R44 registered F-HATU on 09/09/2023 at Issoire
Loss of yaw control during landing, rollover
The pilot, unaccompanied, was hover taxiing in the ground effect to reach the refuelling station. While in hover, he started descending by lowering the collective pitch lever and holding the yaw with the foot pedals. After coming into contact with the paved ground, the helicopter entered a left-hand rotation around its yaw axis. The pilot was unable to counter this movement and the helicopter carried out more than one complete turn. The tail rotor guard and skid and then the main rotor came into contact with the ground. The helicopter rolled over onto its right-
hand side.
The investigation was not able to determine what caused the helicopter to start rotating around its yaw axis; the start of rotation was not controlled by the pilot. An inadequate coordination by the pilot, between the lowering of the collective pitch lever during the descent and the inputs on the pedals might have contributed to it.
When a helicopter starts yawing, the pilot must immediately react with large amplitude inputs, possibly up to full travel and this, until the rotation stops.